Method of making castings.



"No. 740,733. PATENTED 001e, 190a; c. H. BIEEBAUM. METHOD or MAKINGGASTINGS.

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No. 140,733. PATBNTED 001'.- 6,1903.

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No; 740,733. PATENTED OCT. 6, 1903;

7 C. H. BIERBAUM.

METHOD OF MAKING GASTINGS.

APPLICATION FILED FEB 27. 1902.

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7% NITED STAT Tatented (lctober 6, i963.

,oumsrornna H. BIERBAUM, or BUFFALO, NEW YORK.

METHOD OF MAKING CASTINGS.

$PEGIFICATION formingpart of Letters Patent No. 740,733, dated October6, 1903. Application filed February 2'7, 1902. Serial No. 95,856. (Nomodel.)

To all whont it may concern:

Be it known that I, CHRISTOPHER H. BIER- BAUM, a citizen of the UnitedStates, residing at Buffalo, in the county of Erie, in the State of NewYork, have invented new and useful Improvements in Methods of MakingCastings, of which the following is a specification.

This invention relates to a method of casting hardening fluids, such asmolten metals and plastic substances, but is more especially desirablefor castingin metal molds that class of metals and alloys in which themaximum shrinkage occurs at nearly the same temperature at whichsolidification takes place. Characteristic of this class are the alloyscontaining a relatively high percentage of zinc. I'Ieretofore more orless perfect castings of these metals or alloys were produced by the useof sand molds. The heat of the metal upon entering these molds generatedsteam, due to the moisture in the sand, which caused a considerableoxidation to take place. This oxidation is especially injurious inalloys containing aluminium. The scum procured by oxidation is lighterthan the metal and rises to the surface of the molten metal, leaving thelower surface of the metal comparatively free from oxid scum. Thismovement of the scum from the lower to the upper portion of the metal ispossible in sand molds becausethe metal cools slowly in such molds andre-. mains in a molten condition asuflicient time for this purpose.lVhen sand molds are em ployed for casting alloy halfbearings,linings,and sleeves, the mold is usually so arranged that the inner or journalside of the bearing is lowermost, while the outer side thereof isuppermost. By this arrangement of the mold a bearin g-casting isproduced free from oxid scum on its journal side which otherwise wouldbe liable to cut the shaft turning therein, while the oxid scum isgathered on the outer side of the bearing, where it can be dressed ortimed off by a suitable tool, if necessary. I

lVhile serviceable bearings can be produced in sand molds,'the use ofsuch molds is objectionable because of the excessive oxidation producedin the same, which requires considerable trimming of the castings forremoving the oxid scum, and also because of the expense attending theconstruction of an individual mold for each casting.

'When metal or other permanent molds are used for producing alloycastings, oxidation is reduced to a minimum owing to the absence ofmoisture in the mold, the expense of constructing a new mold for eachcasting is avoided, and the castings can be produced more expeditiouslybecause the molten metal cools rapidly in a metal mold. M

The use of metal molds in the same manner described with reference tosand molds is impractical because the rapid cooling of the molten metalin metal molds produces undesirable shrinkage strains in the castingsand prevents the oxid scum from rising to the upper surface of thecastings, which scum is liable to become entrained in the body of thecasting. This renders such castings unsuitable for bearings because thepresence of oxid scum on the journal-surface of the bearing-castingscuts the shaft turning therein.-

One of the objects of my invention is to produce in an expeditiousmanner castings which are full or unshrunk and have no shrinkagestrains. 7

Another object is to avoid the entraining of oxid scum in the body ofthe castings.

My improved method of casting hardening fluids is as follows: After themold has been 1 prepared the same isso placed that that portion which isto be filled first is lowermost. The delivery gate or outlet of thereceptacle, from which the molten metal is supplied, is then so placedthat the metal is delivered quiescently into the mold and withoutfalling freely from the gate to the same. As the metal flows from thegate into the mold one of these members is moved relatively to theother, so that the gate always remains in line or substantially in linewith the level of the liquid in the mold. By this relative move- H mentof the gate and mold the metal when once deposited in the mold is notdisturbed,

but remains at rest, and 'the following new metal is deposited upon thepreceding metal. By thus avoiding agitation of the fluid in the moldafter its deposit oxidation is reduced to a minimum arid a casting isproduced without entrained "scum. A quiescent delivery of the metal intothe mold is furthermore desirable because the process of solidificationcan begin immediately upon depositing the metal, enabling the newincoming metal to take up any shrinkage which takes place duringsolidification and producing a casting which is full and withoutblow-holes. The relative movement of the mold and gate and the rate ofadmission of the metal to the mold are so regulated that filling,shrinking, and solidifying of the metal occur continuously andsimultaneously in different parts of the mold. I

In addition to moving the mold and gate relatively to each other it isdesirable in some forms of castings to tilt the mold gradually either bya simple ora compound movement as the filling thereof progresses for thepurpose of filling the rear end of the mold first and concentrating thefinal or front portion of the mold space to be filled around the gate,thereby enabling the mold to be filled entirely and producing a full andperfect casting.

A machine for practicing my invention is shown in the accompanyingdrawings, which consist of three sheets, andin which- Figure 1 is alongitudinal sectional elevation of a machine for producing the castingshown in Fig. 5. Fig. 2 is a horizontal section thereof in line 2 2,Fig. 1. Fig. 3 is a vertical cross-section in line 3 3, Fig. 1. Fig. 4:is an end elevation thereof. Fig. 5 is a perspective View of a flangedhalf-bearing or semicylindrical lining which may be cast in accordancewith my invention in the machine shown in Figs. 1 to 4. Figs. 6 and 7are diagrams in avertical plane, showing the manner in which the metalis deposited in the mold for casting the half -bearing shown in Fig. 5.Fig. 8 is a plan View of the same. Fig. 9 is a diagram in a verticalplane, illustrating the manner of depositing metal in a mold for castinga fiat rectangular plate. Fig. 10 is a top plan view of the same. Fig.11 is a perspective view of a flanged whole bearing or cylindricalsleeve which may be cast according to my invention. Fig. 12 is asectional elevation of a mold for producing the casting shown in Fig.11. Fig. 13 is a diagram showing the manner of casting a flat triangularplate in accordance with my improved method.

In all of the foregoing figures the arrows show the direction of motionof the parts with which they are associated.

Like letters of reference refer to like parts in the several figures.

c c, which are pivoted by horizontal pins 0 to the upper ends of thestandards I), so that the yoke can swing in a vertical plane.

D represents an axle or arbor projecting rearwardly from the yoke andarranged at right'angles to the pivots o and intersecting their axis.

The mold is constructed wholly of metal and consists, essentially, of afront section or disk E, an inner semicylindrical section F, an outersemicylindrical section G, and bottom plates H H. The disk E is securedto the arbor adjacent to the yoke O and forms the front end of themold-cavity. The disk is provided with a flat rear side or face e, whichis arranged at right angles to the arbor and intersects the axis of theyoke-pivots c. The inner mold-section F bears at its front end againstthe rear side of the disk E and is journaled to turn transversely on thearbor I) by means of two hubs ff, which are mounted on the front andrear ends of the arbor. The inner mold-section is held against axialmovement on the arbor by the disk E, bearing against the front end ofthe inner section, and a head f secured to the rear end of the arbor andengaging the rear end'of the inner section. The outer mold-section G hasits semicylindrical body g arranged concentrically with the innersection andis separated therefrom by an intervening semicylindricalspace 7;, forming the mold-cavity, in which the body A of thehalf-bearing is cast. The rear end of the outer mold-section is providedwith an internal flange g, which rests on the rear end of the innermold-section and forms the rear end of the mold-cavity. The outermold-section is provided at its front end with an offset or enlargedportion g which bears'against the rear side of the disk E and forms,with the latter, the lateral extension 2' of the moldcavity in which theflange a of the half-bearing is cast. The bottom plates H bear at theirfront ends against the rear side of the disk E, while their sides andrear ends bear against the longitudinal edges of the inner and outersections and the internal flange g, respectively, thereby closing thebottom of the moldcavity. The bottom plates are secured permanently tothe inner mold-section by screws j, and the outer mold-section isdetachably held in place by catches in, connecting the same with thebottom plates.

In the use of this machine the inner and outer sections F G of the moldand the bottom plates H in their assembled condition are reversed orgiven a half-turn on the arbor,

this movement causing the front ends of these parts of the mold to sweepover the disk E. One of the bottom plates H is provided with a handle Lfor turning the mold-sections on the arbor. While turning the mold aboutthe arbor the same is also lowered at its rear end, so that whenreversed the mold is tilted or inclined from its front toward its rearend. This tilting of the mold is efiected automatically while turningthe mold by means of an 7 upright. link M, pivoted at its lower end tothe rear end of the base by a swiveling connection m and having itsupper end pivoted eccentrically to the rear hub f of the innermold-section by a swiveling connection m. In the normal position of themold preparatory to being filled the same occupies a horizontal or.nearly horizontal position and the swiveling connection on is below thearbor, as shown by full lines in Figs. 1 and l. Upon reversing the moldits rear end is depressed below the swiveling connection on owing to theeccentric connection with the link M, as shown by dotted lines in Fig.1.

The metal from which the casting is produced is fed into the mold-cavitythrough a gate or inlet passage 41, which is formed in the disk E andcommunicates with the front end of the mold-cavity. As shown in thedrawings, the metal is conducted to the gate by a funnel or filler N,which is secured to the disk E. The gate is located in the disk E on oneside of, the arbor D and substantially at the intersection of the axesof the pivots c and the arbor, whereby the gate remains practicallystationary relative to the mold while the latter is being reversed andtilted.

Preparatory to filling the mold the same is turned to the position shownin full lines in Figs. 1 to 4, in which position its rotary parts arelocated horizontally above the arbor and the bottom of one side of thesemicylindrical mold-cavity is in line with the gate n. The molten metalis now poured into the mold through the gate and at the same time themold is turned about'the arbor, which causes it to be tilted rearwardlyin the direction of the arrows, Figs. 1 and 3.

Although the supply of liquid to the mold is continuous, the same may beregarded as a succession of layers for the purpose of illustration.Viewed in this manner, when an alloy is cast in a metal-mold the processof cooling or solidifying is taking place in the first layer, theprocess of shrinking is taking place in the second layer, while thethird layer is still in a molten state and in condition to supply thenecessary metal for taking up the shrinkage which occurs in the secondlayer, thereby producing a casting which is full and free from sidecavities which are usually present in castings produced by the methodsheretofore employed. Each of the so-called layers of the casting passessuccessively through the steps or stages of filling, shrink: ing, andsolidifying, these stages progressing upwardly in the same order fromone layer to the next above as the mold is turned and the fluid fillsthe same. It will thus be seen that by this manner of using a metal moldin which the liquid hardens rapidly the initial portion of the castingmay be in a completely hardened condition before the metal for the finalportion of the casting has been poured into the mold.

If the mold were simply turned about the arbor without tilting it, thefinal portion of aginary succession of liquid-levels.

the mold-cavity would consist of a long and narrow space which could notbe properly filled from one end of the mold, and a perfect casting couldnot, therefore, be produced. Such anarrow final space in the'mold-cavityis avoided by tilting the mold rearwardly at the same time that it isturned about the arbor when acasting of the form shown in Fig. 5 ismade. The effect of this compound movement is shown in diagrammaticFigs. 6, '7, and 8. By thus tilting the mold rearward gradually as thefilling proceeds at the gate 71, the rear end of the cavity, which'isremote from the gate, is filled in advance of the front part of themold,adjacent to the gate. This causes the unfilled part of the cavityto always fiare outwardly, or toward the gate, from the beginning of thefilling operation at nflwhile the mold is above its longitudinal axis,as shown in Fig. 6, to the completion of that operation at 01 while themold is reversed and below its longitudinal axis, as shown in Fig.WVhile turning the mold around the arbor at the same time that itistilted rearwardlythe socalled layers are laid in the mold obliquely,this formation being shown by the lines a in Figs. 6, 7, and 8, whichrepresent an im- During the filling of the mold, while the same receivesthis compound movement, its cavity gradually contracts from all sidestoward the gate, which action causes the rear end of the cavity to befilled first and concentrates the final or unfilled portion of thecavity at the gate, where the same can be filled completely,

so asto produce a perfect casting.

Owing to the rapid cooling of the metal in a metal mold, the casting iscompletely hardened when the mold reaches the end of its rotary andtilting movement.

Upon releasing the catches 7c the outer mold-section G may be detachedfrom the bottom plates H for removing the finished casting. The outermold-section is then replaced and the mold returned to its initialposition preparatory to producing the next casting.

The compound movement of the mold is also desirable for casting a fiatrectangular plate 0, as shown in Figs. 9 and 10. The

filling of the mold for producing this casting begins at 0" andterminates at 0 When the filling of the mold for casting the plate 0begins, the mold is in a horizontal position, or nearly so,corresponding to theposition of the plate in Fig. 9. As the fillingproceeds the mold is moved laterally in the direction of the arrow, Fig.10, so that the gate moves gradually from 0 to 0 and at the same timethe rear end of the mold is tilted or lowered, as indicated by the arrowin Fig. 9, whereby the rear part of the mold is filled'in advance of thefront part and the mold cavity or space to be filled is graduallyconcentrated around the gate.

For the purpose of producing a casting con sisting of a cylindrical bodyP, having an external annular flange p at one end, as shown in Fig. 11,the mold may be constructed as shown in Fig. 12. In this figure p represents the outer part and p the inner part of the mold, both of whichparts are mounted in any suitable way so that they can be tilted, forinstance, by turning the mold about the center p The inner mold sectionis provided with a filling-gate p and ismovable axially in the outersection. Preparatory to filling the'mold is tilted to substantially theposition shown in Fig. 12, and the inner section is so adjusted that thegate 1) opens into the lowermost part of the mold-cavity. The metal isnow poured through the gate into the mold-cavity and at the same timethe mold is tilted in the direction of the arrow, Fig. 12, and the innermold-section raised in the inner section in the same measure as thefilling of the mold progresses, whereby the liquid metal is deposited inthe mold without any free fall and comes to rest immediately line withthe liquid-level in the mold as the same becomes filled by moving one ofthese members relatively to the other, and at the same time so tiltingthe mold that the end thereof remote from the gate is filled in ad Vanceof the end adjacent to the gate, substantially as set forth.

\Vitness my hand this 26th day of February, 1902.

CHRISTOPHER ll. BIERBAUM.

*itnesses:

THEo. L. PoPP, CARL F. GEYER.

